Supply circuits for radio sets



Aug. 15, 19 33.. J,-G ACEVES Re. 18,916

SUPPLY CIRCUITS FORRADIO SETS Original Filed April 29, 1922 Inven tor Julius GourguesAceves,

orney.

Reissued Aug. 15, 1933 sUrPLY CIRCUITS Fon RADIO SETS 1 Julius 'Gourgues Aceves, New York, N. Y., assignor, by mesne assignments, to Radio Corporation of America, New York, N. Y., a Corporationof Delaware r Original No. 1,622,170, dated March 22, 1927, Serial No. 557,348, April 29, 1922. Application for reissue Mai-ch20, 1929. Serial No. 348,655

.11 Claims. (01. 250 27) This invention relates to radio communication apparatus and the like. More particularly it relates to radio communication apparatus such as receivingsets, and to the manner of supplying energy to the vacuum tubes ofsuch sets.

An object of this invention is to provide for the vacuum tubes of such a set means for supplying from a single source of direct current energy a highpotential for the plates and a W grid bias 10 voltage which is negative for the amplifier tubes.

A further object is to provide alow grid bias .voltage from such source which is positive for the detector tubes. A..further'object of this invention is to provide the source of direct current en- 1 5 .ergy from a commercial alternating current source and deliver direct. current of requisite uniformity and voltages to the several parts of a radio set.

In the accompanying sheet of drawing which forms a part of this specification, the figure is a diagrammatic representationof one embodiment of the invention in a receiving set.

An antenna 1 is connectedto ground through an adjustable condenser 2 and an adjustable inductancecoil3. Therearethreeradiofrequency tubes 4, 5, 5, and a detector tube 6 connected in cascade. The grid of the first radio frequency tube 4 is shown directly connected to the antenna. circuit, the

grids of the second and third radio frequency 3 tubes 5, 5 are each connected to the plates of the preceding radio frequency tube inductively through an amplifying transformer with a primary coil '7 and a secondary coil 8. The inven tion is not limited to any particular number of radiofrequency tubes, nor isthe invention limited to a single detector tube. The gridof the detector tube is connected to the plate of the last radio frequency tube in cascade inductively through an amplifying transformer with a primary coil 9 .and a secondary coil .10. A telephone receiver 11 is connected-to the plate of the detector tube and is shunted by a condenser 12.

Leads .13, 13 are a source of alternating current, for example, 110 volts at sixty cycles, and connect to a'primary coil 14 of a transformer with three secondary coils of which one. of the transformer coils 15 is connected to the filaments of the radio frequency tubes and the detector tube. Two secondary coils 16, 1'7, are connected to two rectifiers 18, 18, the former in a circuit with-the filaments and, each end of the latter to one of the plates of the rectifiers. From. the middle point of one of the secondary coils'connected with the rectifier tubes is a circuit through a filter for suppressing the alternating components, which consistsof a which is connected with the rectifier.

series of sections with choke coils or resistances or both 19, 19 in series and condensers oflarge capacity 20, 20 in multiple. 'From the further end of the filter the circuit is continued through resistance sections 21, 22, 23 to the middle point of the other of the transformer secondary coils The two rectifier tubes are so connected that ea'ch'passes opposite half waves, and the connections to the circuit through the filter andresistance sections is such that both sets of half waves as impressed on this circuit are of thesame sign; Bus-bars 24, 25 are led from the terminals of the series of resistances and between them there will be a difference of potential equal to the voltages of the direct current generated, for example, 125 volts. Bus-bars 26, 27 are ledfrom intermediate points of the series of resistances and the latter is grounded, and the resistances are so proportioned that bus-bar 24 willbe122 volts positive, that busbar 26 will be 3 volts positive and bus-bar 25 will be 3 volts negative, all with respect to the grounded bus-bar. V

The primary coils of the'transformers which connect the radio frequency tubes are connected to the busbar 24 and the far end of the filter. The secondary coils of the transformers which connect the amplifyng tubes are connected to the bus-bar 25 on which there is a negative potential of three volts with respect to the filaments. The secondary coil of the transformer between the last of the amplifying tubes and the detector tube is connected to the bus-bar 26 on which there is a positive potential of three volts with respect to the filaments. The other end of this secondary coil is connected to the grid of the detector tube through a leak resistance 28 shunted by a condenser 29 for the rectification of the signals. The filaments of the amplifying tubes and of the detector tube are connected to two bus-bars 30, 31 which lead from the ends of the secondary coil 15 and the middle point of this secondary coil is grounded so that the filaments will have an average zero potential.

The connection of the antenna circuit to ground is through the resistance 23 and a condenser 32 in parallel with the resistance.

All of the apparatus herein described is of familiar construction. The object of the various bus-bars is to light the filaments and impress upon the grids and plates of the tubes the proper voltages with respect to the filaments for straight amplification or rectification as the case may be. Thus for amplification the grid must be negative with respect to the filament, therefore the voltage of the grids of tubes 4, 5, 5, must be negative with respect to the filaments of these tubes which may be about one-fortieth of the plate voltage; but for rectification the gridmust have a-plus voltage with respect to the filament, and'therefore the grid of .tube 6 must carry a positive charge with respect to its filament, which is customarily about one-fortieth of the plate voltage.

To this end the system is arranged as hereinafter explained so that the voltagesacross the bus-bars are as follows: between 24 and 27, for example, 122 volts; between 25 and 27 minus -3 volts; between 26 and 27 plus 3 volts. The voltage between 30 and 31 is whatever is necessary and convenient to light the filament with a current of low voltage and high amperage.

The difierence of voltageimpressed upon the filaments is determined by the number of turns in the secondary coil 15, and the middle point of this coil is grounded. For use with commercial tubes this coil should develop about six volts.

- The secondary coil 16 of the transformer will supply about seven volts to light the filaments of the rectifiers. Secondary coil 17 is a high voltage winding. From its two halves in opposite phase, alternating current is carried to the plates of the two rectifiers with the result that a pulsating electromotive .force is carried to a filter by which it is converted into direct current potential. The circuit of the direct current is through the coils or resistances of the filter and the resistances 2 1, 22, 23 back to the middle point of secondary coil 17. In ordinary usage bus-bar 25 should have a voltage of about minus 3 volts to which it charges the grids of the amplifier tubes 4, 5, 5; and busbar 26 has a voltage of about plus 3 volts to which it charges the grid of the detector tube 6.

An electrical engineerwill easily determine the resistances necessary to secure the object set forth in any particular apparatus connected up as herein indicated.

Where a set is so connected a slight but not seriously disturbing hum of a frequency of 120 cycles is heard with the telephoneclose to the ear, due to the asymmetrical characteristics of the vacuum tubes and to the shift of thermionic current from one end of the filament to the other as the voltages alternate at the rate of sixty per second. From theoretical considerations confirmed by experiment it is found that the dis-' turbance which causes the hum is proportional to the square of the filament voltage. For this reason resistance of filaments of the amplifying and detector tubes should be as low as practicable if an audio-frequency amplifier is desired. For such use tubes should be operated with as low frequency as practicable.

This application is an application for a reissue of the Letters Patent, No. 1,622,170, granted March 22, 1927 on an application filed by me April 29, 1922, Serial Number 557,348.

What I claim and desire to secure by Letters Patent of the United States, is

1. In a radio set, the combination of an amplitying tube, means for heating the filament of the tube, a connecting circuit, a source of directcurrent energy in separate circuits from the circuit for heating the filament having its? positive end connected to the anode and its negative end connected to the grid of the tube, a resistance connected between the two ends of the direct-current source, and a conductive connection between an intermediate point of the resistance and the filament circuit, whereby the grid is made more negative than the negative end of the filament,

2. In a radio set, the combination of an amplitying, tube having 'anlanode, a filament and a control grid, means for impressing signal variations between said filament and said control grid,

said control gridis made more negative than the negative end of the filament.

3. Radio communication apparatus comprising, an amplifying tube having an anode, a cathode and a control electrode, means for impressing signal variations between said cathode and saidcontrol electrode, a source of electrical energy for heating said cathode, a source of direct current energy separate from said first mentioned source, said source of direct current energy having its positive end connected to said anode and its negative end connected to said control electrode, a resistance connected across said source of direct current,- and a conductive connection'from an intermediate point of said resistance to said cathode whereby said control electrode is maintained more negative than the most negative part of said cathode. v

4. In a radio set, the combination of a space discharge device having an anode, a cathode and a control grid, means for impressing signal variations between said cathode and said control grid, a source of direct current energy, a resistance connected across said source, a connection from the positive end of said resistance to said anode,

a connection from the negative end of said resistance to said control grid, means for conductively connecting the cathode to a single intermediate point on. said resistance, and a separate source of energy for heating said cathode.

5. In a radio communication apparatus the combination of a space discharge device having an anode, a filament and a control electrode, means for impressing signal variations between said filament and said control electrode, a source of energy for heating said filament, a separate source of energy,a resistance shunted across said separate source of energy, a connection from said filament to anintermediate point on said resistance, a connection from said anode to a point'on said resistance at one side of said intermediate point, and a connection from said control electrode to a pointon said resistance at the other side of said intermediate point, whereby the potential of any point on said filament is intermediate between the potentials of said anode and said control electrode.

6. In combination .a space discharge device having an anode, acathode and a control electrode, means for supplying energy to heat the cathode of said device; means for impressing signal variations between the' oathode and the control electrode of said device, a source of energy separate from the first mentionedmeans for supplying unidirectional potential for said device, a resistance shunted across said source 0t energyja connection'irom-an intermediate point on said resistance to said cathode, a connection from" a second point on said resistance to said anode, said second point being positive with respect to said intermediate point,.and aconnection'from athird' point on said: resistance to said control electrode,

said third point. being negative with, respect to,

said intermediate point, whereby the cathode of said device is maintained at a potentialinten; anode and control electrode mediatebetween the potentials.

7.:Incombination a space discharge device having an anode, a. cathode and a control grid,.

an input circuit connected between said cathode ,and said control gridf'means for impressing signal variations upon said input circuit, a source of energy for heating said cathode, a separate source of energy, a grid-biasing resistance connected between said cathode and said control grid, and means forcausing current from said separate source of energy to pass through said grid-biasing resistance in a direction to produce adesi-red normal difference of potential between said cathode and said control grid, said means including a path which is external of said device and which is connected in parallel with'the space discharge path of said device, and connections for supplying current to said gridbiasing resistance :which passes:through the space discharge path of said device and other current which passes through said parallel path.

8. In combination, a space discharge device having an anode, a filament and a control electrode, an input circuit connecting said filament with said control electrode, means for impressing signal variations upon said input circuit, a source of energy for heating said filament, a separate source of energy, a resistance connected between said filament and said control electrode, and means for causing current from said separate source of energy to pass through said resistance in a direction from the filament end to the control electrode end, said means including a path which is external of said device and which is connected in parallel with the space discharge path of said device,- and connections for supplying current from said separate source of energy to said resistance, part of which passes through the space-discharge path of said device and the a remainder of which passes through said parallel path external of said device.

9. In a radio set, the combination of an amplifying tube having an anode, a cathode and a control electrode, means for impressing between said cathode and said control electrode potential variations which correspond to the signal to be amplified, a source of energy for heating said cathode, a separate source of direct current energy, a connection from the positive side of said source of direct current to said anode, a connection from thenegative side of said source of di rectcurrent to said control electrode, a resistance connected between said cathode and the negative side of said source of direct current energy, and means other than the space current path of said amplifying tube and separate from said resistance for providing a direct current path between said cathode and the positive side of said source of direct current energy.

10. A circuit arrangement including a plurality of cascade-connected stages constructed to function for detection and amplification, each stage comprising an electric discharge device having an anode, a cathode, and a control electrode and one of said stages being a detector, a common spect to its cathode and the grid of an amplifier tions from the control electrodes of said devices and from the cathodes of the devices to the impedances arranged to cause said impedances to bias the grid of the detector positively with re- 83 negatively with respect to its cathode, and means for by-passing alternating currents around at least a portion of said impedances. 11. A circuit arrangement including a plurality of cascade-connected stages, each stage comprising an electric discharge device having an anode, a cathode, and a control electrode, a common source of voltage connected-to the anode and cathode of a plurality of stages for supplying space current to said devices, means for holding the cathodes of a plurality of the devices at like direct current potential, impedances traversed by current from said source and connections from the contrdl electrodes of said last-mentionedplurality of'devices and from the cathodes of said last-mentioned devices to the impedances arranged to cause said impedances to bias the grids of such devices differently with respect to their cathodes, and means for by-passing alternating currents around at least a portion of said impedances.

. last-mentioned devices and from the cathodes of the last-mentioned devices to the impedances arranged to cause said impedance to bias the con trol elements of the last-mentioned devices differently with respect to their cathodes, and means for by-passing alternating currents around at least a portion of said impedances.

13. A receiving set comprising an electric discharge device having an anode, a cathode, and a control electrode, a source of voltage connected to the anode and cathode of the device for supplying space current to it, an impedance traversed by current from said source, a connection between the control electrode and the cathode of said device, said connection including at least a portion of said impedance, means for by-passing alternating currents around said impedance, an antenna or other collector of energy, and Con 130 nections from said energy collector to ground including said by-passing means and at least a .portion of said impedance.

14. A multi-stage set having a plurality of casor cade-connected-stages, each comprising an electric discharge device having an anode, a cathode, and a control electrode, a source of voltage connected to the anode and cathode of a plurality of stages for supplying space current to said devices, an-impedance traversed by current from said source, a connection between the control electrode of one device and the cathode of said one device, said connection including at least a portion of said impedance, means for by-passing alternating currents around said impedance, an antenna or other collector of energy, connections from said energy collector to ground including said by-passing means and at least a portion of said impedance, and a variable reactance in the 5 m M v a connectionjforpassing direct current from the,

-, input circuitoithe. first, of the cascade-connected "devices for tuning 'the antenna";

In combm positive sidecf said source of direct current to said anode, a connection from the negative side of said sourceof direct current vto said control, electrode, a cir'cu'it for supplying current fr'om a separate; source of energy 'toheatsaid cathode,

negative side of the output of saidisource of direct current to apoint having approximatelyvthe ti same potentiald'rop to both sides of the cathode heating circuit, saidflast mentionedic'onnection inc1 iiding', a res'istance whereby thepotential of ,1 said cathodewill be'inore positive than thepotentiali of, said control electrode iand a conductive path: across the out iiit of said, sourc'eiofjdirect current, i'said conductive path including a resistance connected between said anode and anothefof the tuhee l ectrodes.

'ral i'.ty ogistages connected inf'cascad e, a space dis- 'chai'gedjevice including an anode, a

cathode and tion an 'ampiifying' tube having an anode.,, a cathode and acontro1'electrode a :source of direct current, a connection from the 16 Ajwa've repatingfsystem comprisinga plua grid electrodeineachof 'saitilamplifiring stages,

'a' circuit for. supplying, cathode heating current to each of said space discharge 'idEViCESQ a source of direct current separate-ifromisaid circuit, and 7 means for suppiyingxanode potentialsxandfipositive and negative'grid polarizingipotentials to said space discharge devices fromasaid' source. 30f direct current, said'means including impedance means traversed "by, current from said source;

1'7.'I n a radio receiver the combination of a detector stage; and" a pluralitv of amplifying stages connected: in cascade, an electron dischargedevice in each stage, an anode, acathode and a gridel'ectrode'in each device, a'source of current for heating said cathodes, a=1ead comrnon to said cathodes, a-source -'of unidirectional volt-- age; aresistancemernber providedw'ith =a phi-- rality'of taps connected acrosslhe voutputof said rectifying means, and connections from'said taps" to the lead common to said cathodes, to the anodes and to the grids of said devicesfor applying;.anode'vo1tage and positive andlnegati've grid biasingvoltages tosaiddevices;

JULIUS, GoURG Es ACEVESV. 

